ElectroClassic EV
Classic Cars Reborn into the Electric Future

Gadget Box

An EV conversion dumps the gas engine and related gear, but brings some additional electronic gadgets to the mix. Creating a nice clean central home for them is better than having them scattered about the car body. The absent fuel tank and evaporator in front of the passenger firewall opened up the perfect space for a control box. I picked up a 6 x 8 inch project box at Radio Shack, and created a mounting brace using a strip of 1/16 inch steel, a bench vise, a hand sledge, and a cordless drill. Some etching primer and a couple coats of satin black made it look like a factory part.


Here is the control box mounted and fully populated with all ancillary components for the front fuel bay area. The location is perfect – adjacent to the charger, heater fan, ceramic core, DC/DC converter, auxiliary battery, and main pack batteries. These various components all need to interact with the box in some manner.


Here’s a closer look inside. At bottom is the Albright 60B contactor that serves the ceramic heater core. The core itself runs on full pack voltage, and needs this power relay to handle the switching. At top is the 120 VDC/25 amp fuse holder and fuse that will protect the heater core from overload. It mediates between the contactor and full positive pack voltage. The DIN rail it’s mounted on has room for future fuses if needed. That cyan square on the right is the MiniBMS control board, which will get more coverage in a future post.


On the left is a connector strip that hosts the 3 amp suppression diodes for the 12 volt coil side of the heater contactor. These diodes prevent back-current induced by the de-energizing relay coil from overloading the fan circuit. The diode at the bottom with the black wire prevents back-current from reentering the positive side of the relay coil circuit, and the others protect all three fan speed circuits. I’m almost sure I could get away with just one diode for the fan speed switch, but in the end I just followed the supplied schematic. Done.


Here’s what the control box will look like when the hood is popped for friends, comrades, spectators and geeks. That triangle hazard sticker I picked up from ComplianceSigns.com will make them think twice about messing with the black and yellow.



3 Responses to “Gadget Box”

  1. Awesome. You have come a long way from the motorized couch!

  2. […] Wiring the heater/fan unit into the EV electrical system is a two-sided process. First the high voltage ceramic heater core needs full pack power of 115 volts DC, and secondly the fan speed control switch needs normal 12 volt DC accessory power. The switch provides three speed settings for the fan motor, but also activates an Albright 60B contactor that controls the high voltage to the heater core. Shown above is the Anderson connector that directs full pack voltage to the ceramic core, regulated by the contactor mounted in the control box. […]

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